Not All Drone Mapping is Created Equal
With the recent advances in drone technology there
are many companies and individuals offering a wide arrange of services to many diverse industries. Many of these services like real estate photography, video
production for products or services, and simple aerial photography are being provided by high quality companies and individuals that provide a tremendous service. These services require the use of photo and video editing software along with other production tools to provide digital and hard copy products such as photos, videos, and hard copy prints.
One service that has become possible, drone mapping, is something that is a little bit different. In many states the production of maps, point clouds, or the related data crosses into the realm of providing Licensed Professional Surveying services. There is also a significant amount of specialized knowledge required to ensure that the data produced has obtained the required accuracies of the client and is free from errors.
For somebody who is obtaining drone mapping services it is imperative that you make sure the person or company providing these services is qualified and competent to deliver the product you need with the required accuracy.
What Is Drone Mapping
Drone mapping is the process of collecting photographs using a drone and then using those photographs to produce highly accurate 3-dimensional point clouds that can be used to map and measure objects on the ground or the ground itself. It is essentially photogrammetry using a drone to collect the photos. Photogrammetry is certainly nothing new having been around since the mid-19th century. Using overlapping photographs, measurements can be made to determine the size, location and elevation of objects in the photos. With the use of PC-based software such as PIX4D and on-line services such as Drone Deploy many overlapping photographs can be processed to produce highly accurate 3D point clouds that can be used to do detailed topographic mapping locating objects on the ground and determining their elevation.
Is Drone Mapping Surveying?
As drone mapping is essentially photogrammetry, it is indeed regulated by professional licensure in many states. Florida for example includes photogrammetry under Chapter 472 of the State Statutes that regulates Professional Surveying Services and defines surveying as follows:
“Practice of surveying and mapping” means, among other things, any professional service or work, the adequate performance of which involves the application of special knowledge of the principles of mathematics, the related physical and applied sciences, and the relevant requirements of law for adequate evidence of the act of measuring, locating, establishing, or reestablishing lines, angles, elevations, natural and manmade features in the air, on the surface and immediate subsurface of the earth, within underground workings, and on the beds or surface of bodies of water, for the purpose of determining, establishing, describing, displaying, or interpreting the facts of size, volume, shape, topography, tidal datum planes, and legal or geodetic location or relocation.
That Statute goes on to further define a Photogrammetrist who is required to be licensed under the Statute as:
“Photogrammetrist” means any person who engages in the practice of surveying and mapping using aerial or terrestrial photography or other sources of images.
It is clear under these definitions that in the State of Florida any mapping done, using a drone, other aircraft, or even ground-based photos, to determine size, shape, volumes, location or elevation is providing Professional Surveying Services. It is imperative that you verify the requirements of surveying licensure in your State, or the State your project is in, before obtaining, or providing, drone mapping services. Obtaining services from unlicensed individuals can severely limit your recourse in the event of problems with the data. Providing Professional Surveying Services without a license is illegal and will result in fines and penalties if it shown you are indeed providing services without a license.
Is Your Provider Qualified?
If you are obtaining services in a State where the service is regulated under the Professional Surveying Services statutes your provider may be qualified to provide the services if they are licensed. While anybody, licensed or not, can purchase a drone and some software, either desktop or on-line service, that certainly does not guarantee they are qualified to provide the service to ensure the data is accurate and complete.
Flying the drone correctly, and with the correct settings, is an acquired skill. There are many factors including exposure for clear photographs based on lighting, correct flying heights to obtain the proper ground sampling distance (GSD) and required accuracy, and flying speed to eliminate image blur are just a few factors that must be considered. While many software packages provide guidance and automate some of things mentioned, only experience and time in the air provides the skill necessary for a successful project.
In addition to the possible need to be a licensed surveyor, all drone pilots who fly for business purposes are required to have an FAA Drone Pilot License under Part 107. Hiring unlicensed pilots will not only almost certainly ensure they are unqualified, you also open you and your company up to significant risk if an accident should happen. In today’s litigious world, if there was an accident that caused physical or property damage, you as the providers’ client is are almost certainly going to be drug into any resulting litigation. This also raises the question of proper insurance – make sure any service provider you choose is properly insured against any accidents that may occur during the drone flight. Also make sure they carry appropriate professional liability insurance to guard against monetary damages that may result from inaccurate data.
“It is imperative that you verify the requirements of surveying licensure in your State, or the State your project is in, before obtaining, or providing, drone mapping services.”
Once the photographs have been obtained (correctly) they must be processed to obtain the point clouds, ortho photos and mosaics, and surfaces that are the deliverables. Processing can be done using several different software packages available as either desktop software or on-line processing packages. I personally prefer the desktop method as it allows for complete control of the processing. Using desktop software, you can adjust the settings used to control how the software processes the photos. You can add or subtract points that are used to calculate how the photos are related to each other in a relative fashion as well as how your model is placed on the surface of the Earth. Projects can be processed several different ways and accuracies compared to obtain the most accurate data as well as verify the validity of the final data products.
While almost all software packages and on-line provide reports regarding the processing of the photographs and the resulting point clouds, not all providers may understand what the reports are telling them. Photogrammetry is a very complicated and mathematically challenging subject. A surveying degree at The University of Florida requires 2 semesters of photogrammetry to learn the processes and mathematics required to obtain accurate results. Obviously with today’s advanced software the need for understanding of all the underlying math is not necessary. What is necessary is the ability to read the reports to understand the results of your processing and the accuracies that have been obtained. Also, to understand if there have been any errors in the processing that may have affected your results.
As you look for drone mapping services use the following checklist to help ask the right questions of potential service providers to make sure the person you use has the right qualifications and capabilities to provide you with reliable data to ensure a successful project.
Checklist for Obtaining Drone Mapping
- Is the provider operating within the Surveying Laws if required?
- Does the provider have a Part 107 FAA license to operate a drone?
- Does the provider carry drone flight insurance in case of an accident?
- Does the provider have adequate Professional Liability Insurance in case of data problems?
- Will the provider be using in-house or on-line processing?
- Do the pilots have adequate experience to ensure good data and safety
- Does the provider understand the software they are using and have the ability to answer questions about the processing of the data and resulting reports?
- Is the provider able to certify the correctness of the data and guarantee its completeness and accuracy?
As this type of mapping is often the basis for future design decisions and calculations, asking these questions up front of any potential drone mapping service provider will help ensure a successful project.
David S. Dagostino, PSM is a Florida Licensed Professional Surveyor and Mapper with over 30 years’ experience in the Surveying field. He is co-owner of both Dagostino & Wood. Inc a full-service surveying and mapping firm and Florida Aerial Survey Technologies a company specializing in drone mapping applications both located in Naples, FL. He is also a graduate of The University of Florida with a B.S. Degree in Surveying & Mapping.